Back in the early 90s, a coworker said he had a CB900 Custom that he gave up on because he dropped a screw down a spark plug hole. Told him I'd pay him $150 if he had the title for it. Deal done. Got it home, Vetter fariing with some small cracks, torn seat. Pulled the head just enough to grab the screw, torqued the head back down, adjusted the valves. Fired right up on fresh plugs. Balanced the carbs, fixed the fairing, got the seat recovered for $50. Cleaned it up, polished the original paint, rode it a few hundred miles. Sold it a week later, easily for $800.